aboutsummaryrefslogtreecommitdiff
path: root/contrib/llvm-project/libcxx/include/__compare/compare_weak_order_fallback.h
blob: b0a04abcaaf03c5331491c53b58b60de8212dd97 (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
//===----------------------------------------------------------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//

#ifndef _LIBCPP___COMPARE_COMPARE_WEAK_ORDER_FALLBACK
#define _LIBCPP___COMPARE_COMPARE_WEAK_ORDER_FALLBACK

#include <__compare/ordering.h>
#include <__compare/weak_order.h>
#include <__config>
#include <__type_traits/decay.h>
#include <__type_traits/is_same.h>
#include <__utility/forward.h>
#include <__utility/priority_tag.h>

#ifndef _LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER
#  pragma GCC system_header
#endif

_LIBCPP_BEGIN_NAMESPACE_STD

#if _LIBCPP_STD_VER >= 20

// [cmp.alg]
namespace __compare_weak_order_fallback {
    struct __fn {
        template<class _Tp, class _Up>
            requires is_same_v<decay_t<_Tp>, decay_t<_Up>>
        _LIBCPP_HIDE_FROM_ABI static constexpr auto
        __go(_Tp&& __t, _Up&& __u, __priority_tag<1>)
            noexcept(noexcept(std::weak_order(std::forward<_Tp>(__t), std::forward<_Up>(__u))))
            -> decltype(      std::weak_order(std::forward<_Tp>(__t), std::forward<_Up>(__u)))
            { return          std::weak_order(std::forward<_Tp>(__t), std::forward<_Up>(__u)); }

        template<class _Tp, class _Up>
            requires is_same_v<decay_t<_Tp>, decay_t<_Up>>
        _LIBCPP_HIDE_FROM_ABI static constexpr auto
        __go(_Tp&& __t, _Up&& __u, __priority_tag<0>)
            noexcept(noexcept(std::forward<_Tp>(__t) == std::forward<_Up>(__u) ? weak_ordering::equivalent :
                              std::forward<_Tp>(__t) < std::forward<_Up>(__u) ? weak_ordering::less :
                              weak_ordering::greater))
            -> decltype(      std::forward<_Tp>(__t) == std::forward<_Up>(__u) ? weak_ordering::equivalent :
                              std::forward<_Tp>(__t) < std::forward<_Up>(__u) ? weak_ordering::less :
                              weak_ordering::greater)
        {
            return            std::forward<_Tp>(__t) == std::forward<_Up>(__u) ? weak_ordering::equivalent :
                              std::forward<_Tp>(__t) < std::forward<_Up>(__u) ? weak_ordering::less :
                              weak_ordering::greater;
        }

        template<class _Tp, class _Up>
        _LIBCPP_HIDE_FROM_ABI constexpr auto operator()(_Tp&& __t, _Up&& __u) const
            noexcept(noexcept(__go(std::forward<_Tp>(__t), std::forward<_Up>(__u), __priority_tag<1>())))
            -> decltype(      __go(std::forward<_Tp>(__t), std::forward<_Up>(__u), __priority_tag<1>()))
            { return          __go(std::forward<_Tp>(__t), std::forward<_Up>(__u), __priority_tag<1>()); }
    };
} // namespace __compare_weak_order_fallback

inline namespace __cpo {
    inline constexpr auto compare_weak_order_fallback = __compare_weak_order_fallback::__fn{};
} // namespace __cpo

#endif // _LIBCPP_STD_VER >= 20

_LIBCPP_END_NAMESPACE_STD

#endif // _LIBCPP___COMPARE_COMPARE_WEAK_ORDER_FALLBACK